Towards experimental realization of the superconductor-semiconductor interface in the YBCO-Si composite system

To study the solid state and chemical interactions between Y1Ba2Cu3O7-delta and Si, resistivity and X-ray diffraction measurements were carried out on Y1Ba2Cu3O7-delta-Si-x compounds with 0 < x > 0.12. The transition temperature T-c was found to be slightly decreased by Si addition up to x = 0.08 and sharply decreased at x = 0.10. The superconducting phase incompletely disappeared at z = 0.12. The resistivity was increased by Si doping and its behavior was changed from a metallic to an insulator and semiconductor-like nature. All peaks of the orthorhombic phase were still present by increasing the Si ratio and new phases were produced which were indexed as mainly barium silicates. At z = 0.12 the orthorhombic phase was greatly decreased and the barium silicate phases were very clearly destroying the superconducting phase. The obtained results are discussed according to the superconductor-semiconductor composite model and with the idea of Bose-Einstein condensation. The superconductor-semiconductor composite as the YBCO-SI system seems to be a key to unlocking some secrets about the mechanisms of high T-c superconductors..